Various 1,3-dioxanes, also designated as cyclic acetals derived from an aldehyde and a 1,3-diol, are known in the perfumery literature.
Thus, in U.S. Pat. No. 4,146,506 perfume compositions comprising a 4-isopropyl-5,5-dimethyldioxane with an C1-C3 alkyl substituent in the 2 position have been described. The 1,3-dioxanes are said to have odour notes ranging from fruity, herbal to woody.
In EP 0 039 029 2-(1'-methylbutyl)-1,3-dioxanes are described which are substituted in the 4 and 5 position with at least 2 and in many cases 3 alkyl groups with a maximum total number of carbon atoms of 6. The compounds are said to have floral and fruity odour notes.
In NL-A-7305487 2-n.butyl-4,4,6-trimethyl-1,3-dioxane is described as having lavender, minty and laurel leaf odour notes. Also described therein are various other 4,4,6-trimethyl-1,3-dioxanes, some of which from S. Arctander, Perfume and Flavor Chemicals, Montclair, N.J., 1969, others from own evaluation. The judgement of their suitability for perfumery is mixed.
In NL-A-7305488 various 2-substituted 4-propyl-5-ethyl-1,3-dioxanes are described, again with mixed opinion as to their suitability for perfumery.
In NL-A-7415594 various 2,4 substituted 1,3-dioxanes (erroneously described as 2,6 substituted) are described, in particular 2-(4'-methylpent(en)yl)-4-methyldioxanes, as having woody, floral and fruity (citrussy) odour notes.
In DE-A-2334378 2-(2'-methyl-1'-propenyl)-1,3-dioxanes with one or more methyl or ethyl groups in the positions 4 and/or 5 and/or 6 are described as having a rose-like odour reminiscent to rose oxide.
Finally, in GB 981,285 various substituted 1,3-dioxanes are described in which the 2 position must be substituted with a C4-C9 alkyl group and the 4 position with a methyl group. These substitution requirement are stressed as importand for obtaining the desired geranium-rose odour.